The senses of touch and proprioception describe the faculty by which external forces are perceived by the body, and how the body recognizes its position in space, respectively. The loss or diminishment of these senses challenges how people interact with each other and their environment.
The complications associated with tactile and proprioceptive insensitivity are wide-ranging; mild levels of insensitivity may go unnoticed, while more severe levels can lead to hand and joint dysfunction, falls, pain, and sometimes even death. People who are readily affected by tactile insensitivity include those with neuropathy, stroke, the elderly, and those with diabetes or who frequently use vibrating hand tools, or work in cooler environments. Others experience a temporary loss of tactile acuity too, including those who wear personal protective equipment (i.e. surgeons).
Stochastic resonance technologies have been used to enhance or restore tactile and proprioceptive sensitivity in humans. Stochastic resonance is a phenomenon whereby the application of electrical or mechanical noise to a non-linear system, such as the human body, can heighten the body's sensory capabilities. Though the mechanisms responsible for stochastic resonance in humans remain unclear, studies show that the application of noise to the skin can increase tactile sensitivity in the nearby regions of the body, enabling one to sense mechanical stimuli of relatively low intensity. Similarly, in studies of elderly subjects, noise delivered transcutaneously to the tendons and metatarsal joints in the foot decreased postural sway and caused a heightened sense of proprioception.
Noise used to elicit the stochastic resonance phenomenon in humans has been either electrical or mechanical in nature, and delivered with multiple frequencies between 0 and 1000 Hz (white or Gaussian noise) at imperceptible levels of intensity. Stochastic resonance technologies face practical limitations. The noise delivery systems and stimulators that are used today are too complicated and cumbersome to be incorporated into an apparatus and used beyond the confines of the laboratory. For instance, a mechanical stochastic resonance system delivers noise via piezoelectric or vibratory shaker apparatuses that require large circuitry. The mechanical apparatus needs to be placed over-top of the skin region that is intended to be sensitized. This necessarily limits the skin area that can be affected. An electrical stochastic resonance apparatus however, delivers noise through surface electrodes that are small, flexible and that can be positioned farther away from targeted receptors. Despite this however, the complicated stimulating paradigm causes the stimulation device and controller to be too large for practical purposes.
Thus, there presently exists a need for an apparatus that can increase tactile and/or proprioceptive sensitivities that is practical for use in the field or at home.